The use of a powder mixture for production of superconductive filaments is taught in the Japanese Journal of Applied Physics, V.26 N.9 Sept. 1987, pp. L1527-L1528, Goto et al. In this article is described a process that involves mixing Y.sub.2 O.sub.3, BaCO.sub.3 and CuO powders, grinding and then heating them at 1223.degree. K. for 5 hours. The product is ground and suspended in an aqueous solution of poly(vinyl alcohol) containing a dispersant. The suspension is then extruded as a filament into an alkaline aqueous solution, collected, neutralized, washed and dried. The filament was then heated to remove volatile components.
The production of an analogous product is described in a subsequent article by Goto et al. in the Japanese Journal of Applied Physics, V26, N.12, December 1987, pp. L 1970-L 1972. This time the powder which has been heated to 1223.degree. K. is ground and suspended in an aqueous solution containing Y, Ba and Cu nitrates as well as polyvinyl alcohol and sodium dodecyl sulfate as a dispersant and then treated as before.